Don’t be so cruel as to ask him to actually do the calculations for even the simplest situation. Just ask him to read the equations and tell you what they mean. If someone can’t even read the equations, can he really know what they have to do with evolution?

We realize that any rigorous explanation of entropy is likely to go over the heads of most readers—so we offer this explanation which does not require calculus and uses water analogies instead.

Imagine you have an empty bucket. You put 5 cups of water in that bucket. Then you put in 2 more cups of water. Then you take out 4 cups. Add another 3 cups. How many cups of water are in the bucket? 5+2-4+3= 6. There are 6 cups of water in the bucket, assuming the bucket doesn’t leak. If the bucket leaks, there is no way of knowing exactly how much water is in the bucket—but you do know is that it is less than 6 cups.

A leaky bucket is an “open system.” A tank with a secure lid, with no leaks, is a “closed system.” If you know how much water you put in a closed system, and how much water you take out, then you know how much water is in the tank at any given time.

In thermodynamics, we talk about heat flow in and out of a system. A perfectly insulated system is a closed system. No heat flows in or out. An open system is like a leaky bucket which allows heat to enter or escape.

A perfect ice chest (if it existed) would be a closed system. If you put hot water and a few ice cubes in the ice chest and closed the lid tightly, the water would melt the ice, and eventually the chest would contain uniformly warm water.

If you waited a little while longer, would the uniformly warm water naturally revert to a few ice cubes in hot water? No. The reason is that uniformly warm water has more entropy (that is, more disorder) than water that is organized into ice cubes and hot water.

Entropy is a measure of disorganization. In a closed system, entropy can never decrease. In a closed system, heat always flows from a hot place to a cold place, warming the cold place up, and cooling the hot place down, until both are the same temperature.

But what about the freezer in your kitchen? If you put a bucket of water in the freezer, heat will flow out of the water, out the coils in the back of the freezer and into your nice, warm kitchen. The water would get even colder, and some of it would freeze. (Eventually, all of it would freeze.) Heat flows from the cold water into warm room, apparently violating the Second Law of Thermodynamics because the entropy has decreased. The entropy decreased because the freezer is an open system, like the leaky bucket, which let some of the entropy leak out.

If you plugged the freezer into a portable gasoline generator, with a tank full of fuel, put the bucket of water in the freezer, inside a perfectly insulated room, fired up the generator, and closed the door, what would happen? The water in the freezer would freeze. The entropy in the freezer would decrease—but the entropy of the room would increase by more than entropy decrease in the freezer, so the total entropy of the closed system (that is, the room and everything in it) would actually increase, in theory. In practice, the generator would eventually run out of fuel, the freezer would stop working, heat would leak from the room into the imperfectly insulated freezer, until everything was the same temperature, and the entropy would be as high as it could get.

When everything is at the same temperature, it is said to be “at equilibrium,” and entropy is at its maximum. Everything is equal temperature, so there will be no heat flow, and no work can be done.

The reason why entropy can decrease in a freezer is because energy flows into the freezer from outside, raising the entropy outside more than the entropy decrease inside. External energy can cause an open system to experience a decrease in entropy—but here’s the point that evolutionists miss. They claim that entropy can decrease on Earth because Earth is an open system, receiving energy from the Sun. They fail to realize that the energy has to be applied in the proper way.

If we put a bucket of ice and water out in the hot summer sunlight, the energy coming from the Sun does not cause more water to freeze. It causes the ice to melt even faster because the energy isn’t harnessed for a purpose as it is in a freezer.

The reason why entropy can decrease inside a freezer is because of clever design. Undirected external energy does not cause entropy to decrease in an open system. The energy has to be applied properly.

Same Equations, Different Situations

There is a marvelous mathematical consistency in nature. For example, the second-order equation that describes the flow of electrical current through an inductor, capacitor, and resistor is exactly the same as the equation that describes what happens in a physical system consisting of a spring, a mass, and friction. This not only allows engineers to simulate physical systems using an electrical circuit, it helps engineers understand how physical and electrical systems work.

In 1948, when Claude Shannon wrote his seminal paper 2 on what would eventually be known as Information Theory, he used the term “entropy” because he recognized the similarity between information flow and heat flow. He explained information in terms of heat because thermodynamic disorder was something engineers already understood.

Some physicists are searching for The Theory of Everything because they recognize that many phenomena are just special cases of one general principle. Engineers familiar with entropy and information recognize that the fundamental concept of entropy applies to biology as well as thermodynamics and information. An understanding of entropy helps engineers understand biology because the principles are the same.